Polycarbonate is a plastic material having a heat deflection temperature of 135° C. or more and can be prepared by melt polycondensation or interfacial polycondensation. Since polycarbonate is transparent and has excellent mechanical properties, it is widely used for exterior decorative products including outdoor structures or indoor products exposed to fluorescent light.
However, due to inferior weather resistance, like most plastics, upon exposure to ultraviolet (UV) radiation, polycarbonate exhibits yellowing, lose of surface gloss, and increased haze. Thus its use in certain applications such as exterior decorative products can be particularly limited.
To protect polycarbonate from UV radiation, UV stabilizers can be added thereto. Although this method is the simplest way to protect polycarbonate from UV radiation, inherent properties of UV stabilizers added to a polycarbonate resin composition can result in limited improvement of an initial yellowness index, heat stability, and weather resistance of the polycarbonate resin composition. Particularly, when conventional UV stabilizers are used alone or as mixtures, polycarbonate resin compositions do not exhibit visible light transmittance. Visible light transmittance is an essential property for polycarbonate resin compositions for exterior decorative purposes.